Superplastic forming (SPF) and quick plastic forming (QPF) methods of shaping sheet materials require high temperature environments to enable the characteristic extraordinary deformation of the sheet material. This high temperature environment is often provided by heated platens of a hydraulic press that subsequently heat sheet forming dies or by using embedded heaters to heat the dies directly. Successful implementation of SPF or QPF only requires that the sheet material is heated to a required temperature to enable the extraordinary deformations.
Induction heating is a technique to heat metal objects. However this technique works best with bulky work pieces such as cam shafts, gears and crank shafts. Heating thin sheet metal with induction techniques is very difficult because the sheet does not have structural rigidity. Deformation of the sheet under electromagnetic forces gets more severe as the temperature rises. As the sheet deforms and moves away from the induction coil, the heating effect becomes de-coupled, which can lead to very localized heating and melting. Induction techniques are able to focus the heating effect but are not as well suited for distributing heat, especially in a work piece with a large surface area to volume ratio.